src/libsystemd-network/sd-radv.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2 /***
   3   Copyright © 2017 Intel Corporation. All rights reserved.
   4 ***/
   5
   6 #include <netinet/icmp6.h>
   7 #include <netinet/in.h>
   8 #include <arpa/inet.h>
   9
  10 #include "sd-radv.h"
  11
  12 #include "alloc-util.h"
  13 #include "dns-domain.h"
  14 #include "ether-addr-util.h"
  15 #include "event-util.h"
  16 #include "fd-util.h"
  17 #include "icmp6-util.h"
  18 #include "in-addr-util.h"
  19 #include "iovec-util.h"
  20 #include "macro.h"
  21 #include "memory-util.h"
  22 #include "ndisc-router-solicit-internal.h"
  23 #include "network-common.h"
  24 #include "radv-internal.h"
  25 #include "random-util.h"
  26 #include "socket-util.h"
  27 #include "string-util.h"
  28 #include "strv.h"
  29 #include "unaligned.h"
  30
  31 int sd_radv_new(sd_radv **ret) {
  32         _cleanup_(sd_radv_unrefp) sd_radv *ra = NULL;
  33
  34         assert_return(ret, -EINVAL);
  35
  36         ra = new(sd_radv, 1);
  37         if (!ra)
  38                 return -ENOMEM;
  39
  40         *ra = (sd_radv) {
  41                 .n_ref = 1,
  42                 .fd = -EBADF,
  43                 .lifetime_usec = RADV_DEFAULT_ROUTER_LIFETIME_USEC,
  44         };
  45
  46         *ret = TAKE_PTR(ra);
  47
  48         return 0;
  49 }
  50
  51 int sd_radv_attach_event(sd_radv *ra, sd_event *event, int64_t priority) {
  52         int r;
  53
  54         assert_return(ra, -EINVAL);
  55         assert_return(!ra->event, -EBUSY);
  56
  57         if (event)
  58                 ra->event = sd_event_ref(event);
  59         else {
  60                 r = sd_event_default(&ra->event);
  61                 if (r < 0)
  62                         return 0;
  63         }
  64
  65         ra->event_priority = priority;
  66
  67         return 0;
  68 }
  69
  70 int sd_radv_detach_event(sd_radv *ra) {
  71
  72         assert_return(ra, -EINVAL);
  73
  74         ra->event = sd_event_unref(ra->event);
  75         return 0;
  76 }
  77
  78 sd_event *sd_radv_get_event(sd_radv *ra) {
  79         assert_return(ra, NULL);
  80
  81         return ra->event;
  82 }
  83
  84 int sd_radv_is_running(sd_radv *ra) {
  85         if (!ra)
  86                 return false;
  87
  88         return ra->state != RADV_STATE_IDLE;
  89 }
  90
  91 static void radv_reset(sd_radv *ra) {
  92         assert(ra);
  93
  94         (void) event_source_disable(ra->timeout_event_source);
  95
  96         ra->recv_event_source = sd_event_source_disable_unref(ra->recv_event_source);
  97
  98         ra->ra_sent = 0;
  99 }
 100
 101 static sd_radv *radv_free(sd_radv *ra) {
 102         if (!ra)
 103                 return NULL;
 104
 105         LIST_CLEAR(prefix, ra->prefixes, sd_radv_prefix_unref);
 106         LIST_CLEAR(prefix, ra->route_prefixes, sd_radv_route_prefix_unref);
 107         LIST_CLEAR(prefix, ra->pref64_prefixes, sd_radv_pref64_prefix_unref);
 108
 109         free(ra->rdnss);
 110         free(ra->dnssl);
 111
 112         radv_reset(ra);
 113
 114         sd_event_source_unref(ra->timeout_event_source);
 115         sd_radv_detach_event(ra);
 116
 117         ra->fd = safe_close(ra->fd);
 118         free(ra->ifname);
 119
 120         return mfree(ra);
 121 }
 122
 123 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv, sd_radv, radv_free);
 124
 125 static bool router_lifetime_is_valid(usec_t lifetime_usec) {
 126         assert_cc(RADV_MAX_ROUTER_LIFETIME_USEC <= UINT16_MAX * USEC_PER_SEC);
 127         return lifetime_usec == 0 ||
 128                 (lifetime_usec >= RADV_MIN_ROUTER_LIFETIME_USEC &&
 129                  lifetime_usec <= RADV_MAX_ROUTER_LIFETIME_USEC);
 130 }
 131
 132 static int radv_send_router(sd_radv *ra, const struct in6_addr *dst, usec_t lifetime_usec) {
 133         assert(ra);
 134         assert(router_lifetime_is_valid(lifetime_usec));
 135
 136         struct sockaddr_in6 dst_addr = {
 137                 .sin6_family = AF_INET6,
 138                 .sin6_addr = IN6_ADDR_ALL_NODES_MULTICAST,
 139         };
 140         struct nd_router_advert adv = {
 141                 .nd_ra_type = ND_ROUTER_ADVERT,
 142                 .nd_ra_router_lifetime = usec_to_be16_sec(lifetime_usec),
 143                 .nd_ra_retransmit = usec_to_be32_msec(ra->retransmit_usec),
 144         };
 145         struct {
 146                 struct nd_opt_hdr opthdr;
 147                 struct ether_addr slladdr;
 148         } _packed_ opt_mac = {
 149                 .opthdr = {
 150                         .nd_opt_type = ND_OPT_SOURCE_LINKADDR,
 151                         .nd_opt_len = DIV_ROUND_UP(sizeof(struct nd_opt_hdr) + sizeof(struct ether_addr), 8),
 152                 },
 153                 .slladdr = ra->mac_addr,
 154         };
 155         struct nd_opt_mtu opt_mtu =  {
 156                 .nd_opt_mtu_type = ND_OPT_MTU,
 157                 .nd_opt_mtu_len = 1,
 158                 .nd_opt_mtu_mtu = htobe32(ra->mtu),
 159         };
 160         /* Reserve iov space for RA header, linkaddr, MTU, N prefixes, N routes, N pref64 prefixes, RDNSS,
 161          * DNSSL, and home agent. */
 162         struct iovec iov[6 + ra->n_prefixes + ra->n_route_prefixes + ra->n_pref64_prefixes];
 163         struct msghdr msg = {
 164                 .msg_name = &dst_addr,
 165                 .msg_namelen = sizeof(dst_addr),
 166                 .msg_iov = iov,
 167         };
 168         usec_t time_now;
 169         int r;
 170
 171         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 172         if (r < 0)
 173                 return r;
 174
 175         if (dst && in6_addr_is_set(dst))
 176                 dst_addr.sin6_addr = *dst;
 177
 178         /* The nd_ra_curhoplimit and nd_ra_flags_reserved fields cannot specified with nd_ra_router_lifetime
 179          * simultaneously in the structured initializer in the above. */
 180         adv.nd_ra_curhoplimit = ra->hop_limit;
 181         adv.nd_ra_flags_reserved = ra->flags;
 182         iov[msg.msg_iovlen++] = IOVEC_MAKE(&adv, sizeof(adv));
 183
 184         /* MAC address is optional, either because the link does not use L2 addresses or load sharing is
 185          * desired. See RFC 4861, Section 4.2. */
 186         if (!ether_addr_is_null(&ra->mac_addr))
 187                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mac, sizeof(opt_mac));
 188
 189         if (ra->mtu > 0)
 190                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&opt_mtu, sizeof(opt_mtu));
 191
 192         LIST_FOREACH(prefix, p, ra->prefixes) {
 193                 usec_t lifetime_valid_usec, lifetime_preferred_usec;
 194
 195                 lifetime_valid_usec = MIN(usec_sub_unsigned(p->valid_until, time_now),
 196                                           p->lifetime_valid_usec);
 197
 198                 lifetime_preferred_usec = MIN3(usec_sub_unsigned(p->preferred_until, time_now),
 199                                                p->lifetime_preferred_usec,
 200                                                lifetime_valid_usec);
 201
 202                 p->opt.lifetime_valid = usec_to_be32_sec(lifetime_valid_usec);
 203                 p->opt.lifetime_preferred = usec_to_be32_sec(lifetime_preferred_usec);
 204
 205                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 206         }
 207
 208         LIST_FOREACH(prefix, rt, ra->route_prefixes) {
 209                 rt->opt.lifetime = usec_to_be32_sec(MIN(usec_sub_unsigned(rt->valid_until, time_now),
 210                                                         rt->lifetime_usec));
 211
 212                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&rt->opt, sizeof(rt->opt));
 213         }
 214
 215         LIST_FOREACH(prefix, p, ra->pref64_prefixes)
 216                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&p->opt, sizeof(p->opt));
 217
 218         if (ra->rdnss)
 219                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->rdnss, ra->rdnss->length * 8);
 220
 221         if (ra->dnssl)
 222                 iov[msg.msg_iovlen++] = IOVEC_MAKE(ra->dnssl, ra->dnssl->length * 8);
 223
 224         if (FLAGS_SET(ra->flags, ND_RA_FLAG_HOME_AGENT)) {
 225                 ra->home_agent.nd_opt_home_agent_info_type = ND_OPT_HOME_AGENT_INFO;
 226                 ra->home_agent.nd_opt_home_agent_info_len = 1;
 227
 228                 /* 0 means to place the current Router Lifetime value */
 229                 if (ra->home_agent.nd_opt_home_agent_info_lifetime == 0)
 230                         ra->home_agent.nd_opt_home_agent_info_lifetime = adv.nd_ra_router_lifetime;
 231
 232                 iov[msg.msg_iovlen++] = IOVEC_MAKE(&ra->home_agent, sizeof(ra->home_agent));
 233         }
 234
 235         if (sendmsg(ra->fd, &msg, 0) < 0)
 236                 return -errno;
 237
 238         return 0;
 239 }
 240
 241 static int radv_process_packet(sd_radv *ra, ICMP6Packet *packet) {
 242         int r;
 243
 244         assert(ra);
 245         assert(packet);
 246
 247         if (icmp6_packet_get_type(packet) != ND_ROUTER_SOLICIT)
 248                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EBADMSG), "Received ICMP6 packet with unexpected type, ignoring.");
 249
 250         _cleanup_(sd_ndisc_router_solicit_unrefp) sd_ndisc_router_solicit *rs = NULL;
 251         rs = ndisc_router_solicit_new(packet);
 252         if (!rs)
 253                 return log_oom_debug();
 254
 255         r = ndisc_router_solicit_parse(ra, rs);
 256         if (r < 0)
 257                 return r;
 258
 259         struct in6_addr src = {};
 260         r = sd_ndisc_router_solicit_get_sender_address(rs, &src);
 261         if (r < 0 && r != -ENODATA) /* null address is allowed */
 262                 return log_radv_errno(ra, r, "Failed to get sender address of RS, ignoring: %m");
 263         if (r >= 0 && in6_addr_equal(&src, &ra->ipv6ll))
 264                 /* This should be definitely caused by a misconfiguration. If we send RA to ourself, the
 265                  * kernel complains about that. Let's ignore the packet. */
 266                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EADDRINUSE), "Received RS from the same interface, ignoring.");
 267
 268         r = radv_send_router(ra, &src, ra->lifetime_usec);
 269         if (r < 0)
 270                 return log_radv_errno(ra, r, "Unable to send solicited Router Advertisement to %s, ignoring: %m", IN6_ADDR_TO_STRING(&src));
 271
 272         log_radv(ra, "Sent solicited Router Advertisement to %s.", IN6_ADDR_TO_STRING(&src));
 273         return 0;
 274 }
 275
 276 static int radv_recv(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
 277         _cleanup_(icmp6_packet_unrefp) ICMP6Packet *packet = NULL;
 278         sd_radv *ra = ASSERT_PTR(userdata);
 279         int r;
 280
 281         assert(fd >= 0);
 282
 283         r = icmp6_packet_receive(fd, &packet);
 284         if (r < 0) {
 285                 log_radv_errno(ra, r, "Failed to receive ICMPv6 packet, ignoring: %m");
 286                 return 0;
 287         }
 288
 289         (void) radv_process_packet(ra, packet);
 290         return 0;
 291 }
 292
 293 static int radv_timeout(sd_event_source *s, uint64_t usec, void *userdata) {
 294         usec_t min_timeout, max_timeout, time_now, timeout;
 295         sd_radv *ra = ASSERT_PTR(userdata);
 296         int r;
 297
 298         assert(s);
 299         assert(ra->event);
 300         assert(router_lifetime_is_valid(ra->lifetime_usec));
 301
 302         r = sd_event_now(ra->event, CLOCK_BOOTTIME, &time_now);
 303         if (r < 0)
 304                 goto fail;
 305
 306         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 307         if (r < 0)
 308                 log_radv_errno(ra, r, "Unable to send Router Advertisement, ignoring: %m");
 309
 310         /* RFC 4861, Section 6.2.4, sending initial Router Advertisements */
 311         if (ra->ra_sent < RADV_MAX_INITIAL_RTR_ADVERTISEMENTS)
 312                 max_timeout = RADV_MAX_INITIAL_RTR_ADVERT_INTERVAL_USEC;
 313         else
 314                 max_timeout = RADV_DEFAULT_MAX_TIMEOUT_USEC;
 315
 316         /* RFC 4861, Section 6.2.1, lifetime must be at least MaxRtrAdvInterval,
 317          * so lower the interval here */
 318         if (ra->lifetime_usec > 0)
 319                 max_timeout = MIN(max_timeout, ra->lifetime_usec);
 320
 321         if (max_timeout >= 9 * USEC_PER_SEC)
 322                 min_timeout = max_timeout / 3;
 323         else
 324                 min_timeout = max_timeout * 3 / 4;
 325
 326         /* RFC 4861, Section 6.2.1.
 327          * MaxRtrAdvInterval MUST be no less than 4 seconds and no greater than 1800 seconds.
 328          * MinRtrAdvInterval MUST be no less than 3 seconds and no greater than .75 * MaxRtrAdvInterval. */
 329         assert(max_timeout >= RADV_MIN_MAX_TIMEOUT_USEC);
 330         assert(max_timeout <= RADV_MAX_MAX_TIMEOUT_USEC);
 331         assert(min_timeout >= RADV_MIN_MIN_TIMEOUT_USEC);
 332         assert(min_timeout <= max_timeout * 3 / 4);
 333
 334         timeout = min_timeout + random_u64_range(max_timeout - min_timeout);
 335         log_radv(ra, "Next Router Advertisement in %s", FORMAT_TIMESPAN(timeout, USEC_PER_SEC));
 336
 337         r = event_reset_time(ra->event, &ra->timeout_event_source,
 338                              CLOCK_BOOTTIME,
 339                              usec_add(time_now, timeout), MSEC_PER_SEC,
 340                              radv_timeout, ra,
 341                              ra->event_priority, "radv-timeout", true);
 342         if (r < 0)
 343                 goto fail;
 344
 345         ra->ra_sent++;
 346
 347         return 0;
 348
 349 fail:
 350         sd_radv_stop(ra);
 351
 352         return 0;
 353 }
 354
 355 int sd_radv_stop(sd_radv *ra) {
 356         int r;
 357
 358         if (!ra)
 359                 return 0;
 360
 361         if (ra->state == RADV_STATE_IDLE)
 362                 return 0;
 363
 364         log_radv(ra, "Stopping IPv6 Router Advertisement daemon");
 365
 366         /* RFC 4861, Section 6.2.5:
 367          * the router SHOULD transmit one or more (but not more than MAX_FINAL_RTR_ADVERTISEMENTS) final
 368          * multicast Router Advertisements on the interface with a Router Lifetime field of zero. */
 369         r = radv_send_router(ra, NULL, 0);
 370         if (r < 0)
 371                 log_radv_errno(ra, r, "Unable to send last Router Advertisement with router lifetime set to zero, ignoring: %m");
 372
 373         radv_reset(ra);
 374         ra->fd = safe_close(ra->fd);
 375         ra->state = RADV_STATE_IDLE;
 376
 377         return 0;
 378 }
 379
 380 static int radv_setup_recv_event(sd_radv *ra) {
 381         int r;
 382
 383         assert(ra);
 384         assert(ra->event);
 385         assert(ra->ifindex > 0);
 386
 387         _cleanup_close_ int fd = -EBADF;
 388         fd = icmp6_bind(ra->ifindex, /* is_router = */ true);
 389         if (fd < 0)
 390                 return fd;
 391
 392         _cleanup_(sd_event_source_unrefp) sd_event_source *s = NULL;
 393         r = sd_event_add_io(ra->event, &s, fd, EPOLLIN, radv_recv, ra);
 394         if (r < 0)
 395                 return r;
 396
 397         r = sd_event_source_set_priority(s, ra->event_priority);
 398         if (r < 0)
 399                 return r;
 400
 401         (void) sd_event_source_set_description(s, "radv-receive-message");
 402
 403         ra->fd = TAKE_FD(fd);
 404         ra->recv_event_source = TAKE_PTR(s);
 405         return 0;
 406 }
 407
 408 int sd_radv_start(sd_radv *ra) {
 409         int r;
 410
 411         assert_return(ra, -EINVAL);
 412         assert_return(ra->event, -EINVAL);
 413         assert_return(ra->ifindex > 0, -EINVAL);
 414
 415         if (ra->state != RADV_STATE_IDLE)
 416                 return 0;
 417
 418         r = radv_setup_recv_event(ra);
 419         if (r < 0)
 420                 goto fail;
 421
 422         r = event_reset_time(ra->event, &ra->timeout_event_source,
 423                              CLOCK_BOOTTIME,
 424                              0, 0,
 425                              radv_timeout, ra,
 426                              ra->event_priority, "radv-timeout", true);
 427         if (r < 0)
 428                 goto fail;
 429
 430         ra->state = RADV_STATE_ADVERTISING;
 431
 432         log_radv(ra, "Started IPv6 Router Advertisement daemon");
 433
 434         return 0;
 435
 436  fail:
 437         radv_reset(ra);
 438
 439         return r;
 440 }
 441
 442 int sd_radv_set_ifindex(sd_radv *ra, int ifindex) {
 443         assert_return(ra, -EINVAL);
 444         assert_return(ifindex > 0, -EINVAL);
 445
 446         if (ra->state != RADV_STATE_IDLE)
 447                 return -EBUSY;
 448
 449         ra->ifindex = ifindex;
 450
 451         return 0;
 452 }
 453
 454 int sd_radv_set_ifname(sd_radv *ra, const char *ifname) {
 455         assert_return(ra, -EINVAL);
 456         assert_return(ifname, -EINVAL);
 457
 458         if (!ifname_valid_full(ifname, IFNAME_VALID_ALTERNATIVE))
 459                 return -EINVAL;
 460
 461         return free_and_strdup(&ra->ifname, ifname);
 462 }
 463
 464 int sd_radv_get_ifname(sd_radv *ra, const char **ret) {
 465         int r;
 466
 467         assert_return(ra, -EINVAL);
 468
 469         r = get_ifname(ra->ifindex, &ra->ifname);
 470         if (r < 0)
 471                 return r;
 472
 473         if (ret)
 474                 *ret = ra->ifname;
 475
 476         return 0;
 477 }
 478
 479 int sd_radv_set_link_local_address(sd_radv *ra, const struct in6_addr *addr) {
 480         assert_return(ra, -EINVAL);
 481         assert_return(!addr || in6_addr_is_link_local(addr), -EINVAL);
 482
 483         if (addr)
 484                 ra->ipv6ll = *addr;
 485         else
 486                 zero(ra->ipv6ll);
 487
 488         return 0;
 489 }
 490
 491 int sd_radv_set_mac(sd_radv *ra, const struct ether_addr *mac_addr) {
 492         assert_return(ra, -EINVAL);
 493
 494         if (ra->state != RADV_STATE_IDLE)
 495                 return -EBUSY;
 496
 497         if (mac_addr)
 498                 ra->mac_addr = *mac_addr;
 499         else
 500                 zero(ra->mac_addr);
 501
 502         return 0;
 503 }
 504
 505 int sd_radv_set_mtu(sd_radv *ra, uint32_t mtu) {
 506         assert_return(ra, -EINVAL);
 507         assert_return(mtu >= 1280, -EINVAL);
 508
 509         ra->mtu = mtu;
 510
 511         return 0;
 512 }
 513
 514 int sd_radv_set_hop_limit(sd_radv *ra, uint8_t hop_limit) {
 515         assert_return(ra, -EINVAL);
 516
 517         if (ra->state != RADV_STATE_IDLE)
 518                 return -EBUSY;
 519
 520         ra->hop_limit = hop_limit;
 521
 522         return 0;
 523 }
 524
 525 int sd_radv_set_retransmit(sd_radv *ra, uint64_t usec) {
 526         assert_return(ra, -EINVAL);
 527
 528         if (ra->state != RADV_STATE_IDLE)
 529                 return -EBUSY;
 530
 531         if (usec > RADV_MAX_RETRANSMIT_USEC)
 532                 return -EINVAL;
 533
 534         ra->retransmit_usec = usec;
 535         return 0;
 536 }
 537
 538 int sd_radv_set_router_lifetime(sd_radv *ra, uint64_t usec) {
 539         assert_return(ra, -EINVAL);
 540
 541         if (ra->state != RADV_STATE_IDLE)
 542                 return -EBUSY;
 543
 544         if (!router_lifetime_is_valid(usec))
 545                 return -EINVAL;
 546
 547         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 548          * to (00) by the sender..." */
 549         if (usec == 0 &&
 550             (ra->flags & (0x3 << 3)) != (SD_NDISC_PREFERENCE_MEDIUM << 3))
 551                 return -EINVAL;
 552
 553         ra->lifetime_usec = usec;
 554         return 0;
 555 }
 556
 557 int sd_radv_set_managed_information(sd_radv *ra, int managed) {
 558         assert_return(ra, -EINVAL);
 559
 560         if (ra->state != RADV_STATE_IDLE)
 561                 return -EBUSY;
 562
 563         SET_FLAG(ra->flags, ND_RA_FLAG_MANAGED, managed);
 564
 565         return 0;
 566 }
 567
 568 int sd_radv_set_other_information(sd_radv *ra, int other) {
 569         assert_return(ra, -EINVAL);
 570
 571         if (ra->state != RADV_STATE_IDLE)
 572                 return -EBUSY;
 573
 574         SET_FLAG(ra->flags, ND_RA_FLAG_OTHER, other);
 575
 576         return 0;
 577 }
 578
 579 int sd_radv_set_preference(sd_radv *ra, unsigned preference) {
 580         assert_return(ra, -EINVAL);
 581         assert_return(IN_SET(preference,
 582                              SD_NDISC_PREFERENCE_LOW,
 583                              SD_NDISC_PREFERENCE_MEDIUM,
 584                              SD_NDISC_PREFERENCE_HIGH), -EINVAL);
 585
 586         /* RFC 4191, Section 2.2, "...If the Router Lifetime is zero, the preference value MUST be set
 587          * to (00) by the sender..." */
 588         if (ra->lifetime_usec == 0 && preference != SD_NDISC_PREFERENCE_MEDIUM)
 589                 return -EINVAL;
 590
 591         ra->flags = (ra->flags & ~(0x3 << 3)) | (preference << 3);
 592
 593         return 0;
 594 }
 595
 596 int sd_radv_set_home_agent_information(sd_radv *ra, int home_agent) {
 597         assert_return(ra, -EINVAL);
 598
 599         if (ra->state != RADV_STATE_IDLE)
 600                 return -EBUSY;
 601
 602         SET_FLAG(ra->flags, ND_RA_FLAG_HOME_AGENT, home_agent);
 603
 604         return 0;
 605 }
 606
 607 int sd_radv_set_home_agent_preference(sd_radv *ra, uint16_t preference) {
 608         assert_return(ra, -EINVAL);
 609
 610         if (ra->state != RADV_STATE_IDLE)
 611                 return -EBUSY;
 612
 613         ra->home_agent.nd_opt_home_agent_info_preference = htobe16(preference);
 614
 615         return 0;
 616 }
 617
 618 int sd_radv_set_home_agent_lifetime(sd_radv *ra, uint64_t lifetime_usec) {
 619         assert_return(ra, -EINVAL);
 620
 621         if (ra->state != RADV_STATE_IDLE)
 622                 return -EBUSY;
 623
 624         if (lifetime_usec > RADV_HOME_AGENT_MAX_LIFETIME_USEC)
 625                 return -EINVAL;
 626
 627         ra->home_agent.nd_opt_home_agent_info_lifetime = usec_to_be16_sec(lifetime_usec);
 628         return 0;
 629 }
 630
 631 int sd_radv_add_prefix(sd_radv *ra, sd_radv_prefix *p) {
 632         sd_radv_prefix *found = NULL;
 633         int r;
 634
 635         assert_return(ra, -EINVAL);
 636         assert_return(p, -EINVAL);
 637
 638         /* Refuse prefixes that don't have a prefix set */
 639         if (in6_addr_is_null(&p->opt.in6_addr))
 640                 return -ENOEXEC;
 641
 642         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 643
 644         LIST_FOREACH(prefix, cur, ra->prefixes) {
 645                 r = in_addr_prefix_intersect(AF_INET6,
 646                                              (const union in_addr_union*) &cur->opt.in6_addr,
 647                                              cur->opt.prefixlen,
 648                                              (const union in_addr_union*) &p->opt.in6_addr,
 649                                              p->opt.prefixlen);
 650                 if (r < 0)
 651                         return r;
 652                 if (r == 0)
 653                         continue;
 654
 655                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 656                         found = cur;
 657                         break;
 658                 }
 659
 660                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 661                                       "IPv6 prefix %s conflicts with %s, ignoring.",
 662                                       addr_p,
 663                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 664         }
 665
 666         if (found) {
 667                 /* p and cur may be equivalent. First increment the reference counter. */
 668                 sd_radv_prefix_ref(p);
 669
 670                 /* Then, remove the old entry. */
 671                 LIST_REMOVE(prefix, ra->prefixes, found);
 672                 sd_radv_prefix_unref(found);
 673
 674                 /* Finally, add the new entry. */
 675                 LIST_APPEND(prefix, ra->prefixes, p);
 676
 677                 log_radv(ra, "Updated/replaced IPv6 prefix %s (preferred: %s, valid: %s)",
 678                          addr_p,
 679                          FORMAT_TIMESPAN(p->lifetime_preferred_usec, USEC_PER_SEC),
 680                          FORMAT_TIMESPAN(p->lifetime_valid_usec, USEC_PER_SEC));
 681         } else {
 682                 /* The prefix is new. Let's simply add it. */
 683
 684                 sd_radv_prefix_ref(p);
 685                 LIST_APPEND(prefix, ra->prefixes, p);
 686                 ra->n_prefixes++;
 687
 688                 log_radv(ra, "Added prefix %s", addr_p);
 689         }
 690
 691         if (ra->state == RADV_STATE_IDLE)
 692                 return 0;
 693
 694         if (ra->ra_sent == 0)
 695                 return 0;
 696
 697         /* If RAs have already been sent, send an RA immediately to announce the newly-added prefix */
 698         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 699         if (r < 0)
 700                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added prefix %s, ignoring: %m", addr_p);
 701         else
 702                 log_radv(ra, "Sent Router Advertisement for added/updated prefix %s.", addr_p);
 703
 704         return 0;
 705 }
 706
 707 void sd_radv_remove_prefix(
 708                 sd_radv *ra,
 709                 const struct in6_addr *prefix,
 710                 unsigned char prefixlen) {
 711
 712         if (!ra)
 713                 return;
 714
 715         if (!prefix)
 716                 return;
 717
 718         LIST_FOREACH(prefix, cur, ra->prefixes) {
 719                 if (prefixlen != cur->opt.prefixlen)
 720                         continue;
 721
 722                 if (!in6_addr_equal(prefix, &cur->opt.in6_addr))
 723                         continue;
 724
 725                 LIST_REMOVE(prefix, ra->prefixes, cur);
 726                 ra->n_prefixes--;
 727                 sd_radv_prefix_unref(cur);
 728                 return;
 729         }
 730 }
 731
 732 int sd_radv_add_route_prefix(sd_radv *ra, sd_radv_route_prefix *p) {
 733         sd_radv_route_prefix *found = NULL;
 734         int r;
 735
 736         assert_return(ra, -EINVAL);
 737         assert_return(p, -EINVAL);
 738
 739         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->opt.in6_addr, p->opt.prefixlen);
 740
 741         LIST_FOREACH(prefix, cur, ra->route_prefixes) {
 742                 r = in_addr_prefix_intersect(AF_INET6,
 743                                              (const union in_addr_union*) &cur->opt.in6_addr,
 744                                              cur->opt.prefixlen,
 745                                              (const union in_addr_union*) &p->opt.in6_addr,
 746                                              p->opt.prefixlen);
 747                 if (r < 0)
 748                         return r;
 749                 if (r == 0)
 750                         continue;
 751
 752                 if (cur->opt.prefixlen == p->opt.prefixlen) {
 753                         found = cur;
 754                         break;
 755                 }
 756
 757                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 758                                       "IPv6 route prefix %s conflicts with %s, ignoring.",
 759                                       addr_p,
 760                                       IN6_ADDR_PREFIX_TO_STRING(&cur->opt.in6_addr, cur->opt.prefixlen));
 761         }
 762
 763         if (found) {
 764                 /* p and cur may be equivalent. First increment the reference counter. */
 765                 sd_radv_route_prefix_ref(p);
 766
 767                 /* Then, remove the old entry. */
 768                 LIST_REMOVE(prefix, ra->route_prefixes, found);
 769                 sd_radv_route_prefix_unref(found);
 770
 771                 /* Finally, add the new entry. */
 772                 LIST_APPEND(prefix, ra->route_prefixes, p);
 773
 774                 log_radv(ra, "Updated/replaced IPv6 route prefix %s (lifetime: %s)",
 775                          strna(addr_p),
 776                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 777         } else {
 778                 /* The route prefix is new. Let's simply add it. */
 779
 780                 sd_radv_route_prefix_ref(p);
 781                 LIST_APPEND(prefix, ra->route_prefixes, p);
 782                 ra->n_route_prefixes++;
 783
 784                 log_radv(ra, "Added route prefix %s", strna(addr_p));
 785         }
 786
 787         if (ra->state == RADV_STATE_IDLE)
 788                 return 0;
 789
 790         if (ra->ra_sent == 0)
 791                 return 0;
 792
 793         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 794         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 795         if (r < 0)
 796                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added route prefix %s, ignoring: %m",
 797                                strna(addr_p));
 798         else
 799                 log_radv(ra, "Sent Router Advertisement for added route prefix %s.", strna(addr_p));
 800
 801         return 0;
 802 }
 803
 804 int sd_radv_add_pref64_prefix(sd_radv *ra, sd_radv_pref64_prefix *p) {
 805         sd_radv_pref64_prefix *found = NULL;
 806         int r;
 807
 808         assert_return(ra, -EINVAL);
 809         assert_return(p, -EINVAL);
 810
 811         const char *addr_p = IN6_ADDR_PREFIX_TO_STRING(&p->in6_addr, p->prefixlen);
 812
 813         LIST_FOREACH(prefix, cur, ra->pref64_prefixes) {
 814                 r = in_addr_prefix_intersect(AF_INET6,
 815                                              (const union in_addr_union*) &cur->in6_addr,
 816                                              cur->prefixlen,
 817                                              (const union in_addr_union*) &p->in6_addr,
 818                                              p->prefixlen);
 819                 if (r < 0)
 820                         return r;
 821                 if (r == 0)
 822                         continue;
 823
 824                 if (cur->prefixlen == p->prefixlen) {
 825                         found = cur;
 826                         break;
 827                 }
 828
 829                 return log_radv_errno(ra, SYNTHETIC_ERRNO(EEXIST),
 830                                       "IPv6 PREF64 prefix %s conflicts with %s, ignoring.",
 831                                       addr_p,
 832                                       IN6_ADDR_PREFIX_TO_STRING(&cur->in6_addr, cur->prefixlen));
 833         }
 834
 835         if (found) {
 836                 /* p and cur may be equivalent. First increment the reference counter. */
 837                 sd_radv_pref64_prefix_ref(p);
 838
 839                 /* Then, remove the old entry. */
 840                 LIST_REMOVE(prefix, ra->pref64_prefixes, found);
 841                 sd_radv_pref64_prefix_unref(found);
 842
 843                 /* Finally, add the new entry. */
 844                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 845
 846                 log_radv(ra, "Updated/replaced IPv6 PREF64 prefix %s (lifetime: %s)",
 847                          strna(addr_p),
 848                          FORMAT_TIMESPAN(p->lifetime_usec, USEC_PER_SEC));
 849         } else {
 850                 /* The route prefix is new. Let's simply add it. */
 851
 852                 sd_radv_pref64_prefix_ref(p);
 853                 LIST_APPEND(prefix, ra->pref64_prefixes, p);
 854                 ra->n_pref64_prefixes++;
 855
 856                 log_radv(ra, "Added PREF64 prefix %s", strna(addr_p));
 857         }
 858
 859         if (ra->state == RADV_STATE_IDLE)
 860                 return 0;
 861
 862         if (ra->ra_sent == 0)
 863                 return 0;
 864
 865         /* If RAs have already been sent, send an RA immediately to announce the newly-added route prefix */
 866         r = radv_send_router(ra, NULL, ra->lifetime_usec);
 867         if (r < 0)
 868                 log_radv_errno(ra, r, "Unable to send Router Advertisement for added PREF64 prefix %s, ignoring: %m",
 869                                strna(addr_p));
 870         else
 871                 log_radv(ra, "Sent Router Advertisement for added PREF64 prefix %s.", strna(addr_p));
 872
 873         return 0;
 874 }
 875
 876 int sd_radv_set_rdnss(
 877                 sd_radv *ra,
 878                 uint64_t lifetime_usec,
 879                 const struct in6_addr *dns,
 880                 size_t n_dns) {
 881
 882         _cleanup_free_ struct sd_radv_opt_dns *opt_rdnss = NULL;
 883         size_t len;
 884
 885         assert_return(ra, -EINVAL);
 886         assert_return(n_dns < 128, -EINVAL);
 887
 888         if (lifetime_usec > RADV_RDNSS_MAX_LIFETIME_USEC)
 889                 return -EINVAL;
 890
 891         if (!dns || n_dns == 0) {
 892                 ra->rdnss = mfree(ra->rdnss);
 893                 ra->n_rdnss = 0;
 894
 895                 return 0;
 896         }
 897
 898         len = sizeof(struct sd_radv_opt_dns) + sizeof(struct in6_addr) * n_dns;
 899
 900         opt_rdnss = malloc0(len);
 901         if (!opt_rdnss)
 902                 return -ENOMEM;
 903
 904         opt_rdnss->type = RADV_OPT_RDNSS;
 905         opt_rdnss->length = len / 8;
 906         opt_rdnss->lifetime = usec_to_be32_sec(lifetime_usec);
 907
 908         memcpy(opt_rdnss + 1, dns, n_dns * sizeof(struct in6_addr));
 909
 910         free_and_replace(ra->rdnss, opt_rdnss);
 911
 912         ra->n_rdnss = n_dns;
 913
 914         return 0;
 915 }
 916
 917 int sd_radv_set_dnssl(
 918                 sd_radv *ra,
 919                 uint64_t lifetime_usec,
 920                 char **search_list) {
 921
 922         _cleanup_free_ struct sd_radv_opt_dns *opt_dnssl = NULL;
 923         size_t len = 0;
 924         uint8_t *p;
 925
 926         assert_return(ra, -EINVAL);
 927
 928         if (lifetime_usec > RADV_DNSSL_MAX_LIFETIME_USEC)
 929                 return -EINVAL;
 930
 931         if (strv_isempty(search_list)) {
 932                 ra->dnssl = mfree(ra->dnssl);
 933                 return 0;
 934         }
 935
 936         STRV_FOREACH(s, search_list)
 937                 len += strlen(*s) + 2;
 938
 939         len = (sizeof(struct sd_radv_opt_dns) + len + 7) & ~0x7;
 940
 941         opt_dnssl = malloc0(len);
 942         if (!opt_dnssl)
 943                 return -ENOMEM;
 944
 945         opt_dnssl->type = RADV_OPT_DNSSL;
 946         opt_dnssl->length = len / 8;
 947         opt_dnssl->lifetime = usec_to_be32_sec(lifetime_usec);
 948
 949         p = (uint8_t *)(opt_dnssl + 1);
 950         len -= sizeof(struct sd_radv_opt_dns);
 951
 952         STRV_FOREACH(s, search_list) {
 953                 int r;
 954
 955                 r = dns_name_to_wire_format(*s, p, len, false);
 956                 if (r < 0)
 957                         return r;
 958
 959                 if (len < (size_t)r)
 960                         return -ENOBUFS;
 961
 962                 p += r;
 963                 len -= r;
 964         }
 965
 966         free_and_replace(ra->dnssl, opt_dnssl);
 967
 968         return 0;
 969 }
 970
 971 int sd_radv_prefix_new(sd_radv_prefix **ret) {
 972         sd_radv_prefix *p;
 973
 974         assert_return(ret, -EINVAL);
 975
 976         p = new(sd_radv_prefix, 1);
 977         if (!p)
 978                 return -ENOMEM;
 979
 980         *p = (sd_radv_prefix) {
 981                 .n_ref = 1,
 982
 983                 .opt.type = ND_OPT_PREFIX_INFORMATION,
 984                 .opt.length = (sizeof(p->opt) - 1)/8 + 1,
 985                 .opt.prefixlen = 64,
 986
 987                 /* RFC 4861, Section 6.2.1 */
 988                 .opt.flags = ND_OPT_PI_FLAG_ONLINK|ND_OPT_PI_FLAG_AUTO,
 989
 990                 .lifetime_valid_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
 991                 .lifetime_preferred_usec = RADV_DEFAULT_PREFERRED_LIFETIME_USEC,
 992                 .valid_until = USEC_INFINITY,
 993                 .preferred_until = USEC_INFINITY,
 994         };
 995
 996         *ret = p;
 997         return 0;
 998 }
 999
1000 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_prefix, sd_radv_prefix, mfree);
1001
1002 int sd_radv_prefix_set_prefix(
1003                 sd_radv_prefix *p,
1004                 const struct in6_addr *in6_addr,
1005                 unsigned char prefixlen) {
1006
1007         assert_return(p, -EINVAL);
1008         assert_return(in6_addr, -EINVAL);
1009
1010         if (prefixlen < 3 || prefixlen > 128)
1011                 return -EINVAL;
1012
1013         if (prefixlen > 64)
1014                 /* unusual but allowed, log it */
1015                 log_radv(NULL, "Unusual prefix length %d greater than 64", prefixlen);
1016
1017         p->opt.in6_addr = *in6_addr;
1018         p->opt.prefixlen = prefixlen;
1019
1020         return 0;
1021 }
1022
1023 int sd_radv_prefix_get_prefix(
1024                 sd_radv_prefix *p,
1025                 struct in6_addr *ret_in6_addr,
1026                 unsigned char *ret_prefixlen) {
1027
1028         assert_return(p, -EINVAL);
1029         assert_return(ret_in6_addr, -EINVAL);
1030         assert_return(ret_prefixlen, -EINVAL);
1031
1032         *ret_in6_addr = p->opt.in6_addr;
1033         *ret_prefixlen = p->opt.prefixlen;
1034
1035         return 0;
1036 }
1037
1038 int sd_radv_prefix_set_onlink(sd_radv_prefix *p, int onlink) {
1039         assert_return(p, -EINVAL);
1040
1041         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_ONLINK, onlink);
1042
1043         return 0;
1044 }
1045
1046 int sd_radv_prefix_set_address_autoconfiguration(sd_radv_prefix *p, int address_autoconfiguration) {
1047         assert_return(p, -EINVAL);
1048
1049         SET_FLAG(p->opt.flags, ND_OPT_PI_FLAG_AUTO, address_autoconfiguration);
1050
1051         return 0;
1052 }
1053
1054 int sd_radv_prefix_set_valid_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1055         assert_return(p, -EINVAL);
1056
1057         p->lifetime_valid_usec = lifetime_usec;
1058         p->valid_until = valid_until;
1059
1060         return 0;
1061 }
1062
1063 int sd_radv_prefix_set_preferred_lifetime(sd_radv_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1064         assert_return(p, -EINVAL);
1065
1066         p->lifetime_preferred_usec = lifetime_usec;
1067         p->preferred_until = valid_until;
1068
1069         return 0;
1070 }
1071
1072 int sd_radv_route_prefix_new(sd_radv_route_prefix **ret) {
1073         sd_radv_route_prefix *p;
1074
1075         assert_return(ret, -EINVAL);
1076
1077         p = new(sd_radv_route_prefix, 1);
1078         if (!p)
1079                 return -ENOMEM;
1080
1081         *p = (sd_radv_route_prefix) {
1082                 .n_ref = 1,
1083
1084                 .opt.type = RADV_OPT_ROUTE_INFORMATION,
1085                 .opt.length = DIV_ROUND_UP(sizeof(p->opt), 8),
1086                 .opt.prefixlen = 64,
1087
1088                 .lifetime_usec = RADV_DEFAULT_VALID_LIFETIME_USEC,
1089                 .valid_until = USEC_INFINITY,
1090         };
1091
1092         *ret = p;
1093         return 0;
1094 }
1095
1096 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_route_prefix, sd_radv_route_prefix, mfree);
1097
1098 int sd_radv_route_prefix_set_prefix(
1099                 sd_radv_route_prefix *p,
1100                 const struct in6_addr *in6_addr,
1101                 unsigned char prefixlen) {
1102
1103         assert_return(p, -EINVAL);
1104         assert_return(in6_addr, -EINVAL);
1105
1106         if (prefixlen > 128)
1107                 return -EINVAL;
1108
1109         if (prefixlen > 64)
1110                 /* unusual but allowed, log it */
1111                 log_radv(NULL, "Unusual prefix length %u greater than 64", prefixlen);
1112
1113         p->opt.in6_addr = *in6_addr;
1114         p->opt.prefixlen = prefixlen;
1115
1116         return 0;
1117 }
1118
1119 int sd_radv_route_prefix_set_lifetime(sd_radv_route_prefix *p, uint64_t lifetime_usec, uint64_t valid_until) {
1120         assert_return(p, -EINVAL);
1121
1122         p->lifetime_usec = lifetime_usec;
1123         p->valid_until = valid_until;
1124
1125         return 0;
1126 }
1127
1128 int sd_radv_pref64_prefix_new(sd_radv_pref64_prefix **ret) {
1129         sd_radv_pref64_prefix *p;
1130
1131         assert_return(ret, -EINVAL);
1132
1133         p = new(sd_radv_pref64_prefix, 1);
1134         if (!p)
1135                 return -ENOMEM;
1136
1137         *p = (sd_radv_pref64_prefix) {
1138                 .n_ref = 1,
1139
1140                 .opt.type = RADV_OPT_PREF64,
1141                 .opt.length = 2,
1142         };
1143
1144         *ret = p;
1145         return 0;
1146 }
1147
1148 DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(sd_radv_pref64_prefix, sd_radv_pref64_prefix, mfree);
1149
1150 int sd_radv_pref64_prefix_set_prefix(
1151                 sd_radv_pref64_prefix *p,
1152                 const struct in6_addr *prefix,
1153                 uint8_t prefixlen,
1154                 uint64_t lifetime_usec) {
1155
1156         uint16_t pref64_lifetime;
1157         uint8_t prefixlen_code;
1158         int r;
1159
1160         assert_return(p, -EINVAL);
1161         assert_return(prefix, -EINVAL);
1162
1163         r = pref64_prefix_length_to_plc(prefixlen, &prefixlen_code);
1164         if (r < 0)
1165                 return log_radv_errno(NULL, r,
1166                                       "Unsupported PREF64 prefix length %u. Valid lengths are 32, 40, 48, 56, 64 and 96", prefixlen);
1167
1168         if (lifetime_usec > PREF64_MAX_LIFETIME_USEC)
1169                 return -EINVAL;
1170
1171         /* RFC 8781 - 4.1 rounding up lifetime to multiply of 8 */
1172         pref64_lifetime = DIV_ROUND_UP(lifetime_usec, 8 * USEC_PER_SEC) << 3;
1173         pref64_lifetime |= prefixlen_code;
1174
1175         unaligned_write_be16(&p->opt.lifetime_and_plc, pref64_lifetime);
1176         memcpy(&p->opt.prefix, prefix, sizeof(p->opt.prefix));
1177
1178         p->in6_addr = *prefix;
1179         p->prefixlen = prefixlen;
1180
1181         return 0;
1182 }